Add tests for argp_error and argp_failure with floating-point parameters

The functions argp_error and argp_failure, from argp.h, have a format
string as parameter, which can possibly request the printing of
floating-point values.  These values could be of long double type, which
can have different formats, depending on the architecture and on
compilation parameters (for instance, on powerpc, long double values can
have double format (-mlong-double-64) or IBM Extended Precision format
(-mlong-double-128)).

This patch adds tests for argp_error and argp_failure that contain a
format string with double and long double conversion specifiers ('%f'
and '%Lf').  These tests automatically check that the default format of
the long double type works.  A future patch will extend the test for
platforms that can have an optional format for long double.

Tested for powerpc64le.

	* argp/Makefile (tests): Add tst-ldbl-argp.
	* argp/tst-ldbl-argp.c: New file.

2 files changed, 111 insertions, 1 deletions

diff --git a/argp/Makefile b/argp/Makefile
index 6e4799c..2ea7118 100644
--- a/argp/Makefile
+++ b/argp/Makefile
@@ -26,7 +26,8 @@ headers		= argp.h
 routines	= $(addprefix argp-, ba fmtstream fs-xinl help parse pv \
 				     pvh xinl eexst)
 
-tests		= argp-test tst-argp1 bug-argp1 tst-argp2 bug-argp2
+tests		= argp-test tst-argp1 bug-argp1 tst-argp2 bug-argp2 \
+		  tst-ldbl-argp
 
 CFLAGS-argp-help.c += $(uses-callbacks) -fexceptions
 CFLAGS-argp-parse.c += $(uses-callbacks)
diff --git a/argp/tst-ldbl-argp.c b/argp/tst-ldbl-argp.c
new file mode 100644
index 0000000..4465f81
--- /dev/null
+++ b/argp/tst-ldbl-argp.c
@@ -0,0 +1,109 @@
+/* Testing of long double conversions in argp.h functions.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <argp.h>
+#include <string.h>
+
+#include <support/capture_subprocess.h>
+#include <support/check.h>
+
+static const struct argp_option
+options[] =
+{
+  { "error", 'e', "format", OPTION_ARG_OPTIONAL,
+    "Run argp_error function with a format string", 0 },
+  { "failure", 'f', "format", OPTION_ARG_OPTIONAL,
+    "Run argp_failure function with a format string", 0 },
+  { NULL, 0, NULL, 0, NULL }
+};
+
+static error_t
+parser (int key, char *arg, struct argp_state *state)
+{
+  switch (key)
+    {
+      case 'e':
+	argp_error (state, "%Lf%f%Lf%f", (long double) -1, (double) -2,
+		    (long double) -3, (double) -4);
+	break;
+      case 'f':
+	argp_failure (state, 0, 0, "%Lf%f%Lf%f", (long double) -1,
+		      (double) -2, (long double) -3, (double) -4);
+	break;
+      default:
+	return ARGP_ERR_UNKNOWN;
+    }
+  return 0;
+}
+
+static struct argp
+argp =
+{
+  options, parser
+};
+
+int argc = 2;
+char *argv[3] = { (char *) "test-argp", NULL, NULL };
+
+static void
+do_test_call (void)
+{
+  int remaining;
+  argp_parse (&argp, argc, argv, 0, &remaining, NULL);
+}
+
+static int
+do_one_test (const char *expected)
+{
+  struct support_capture_subprocess result;
+  result = support_capture_subprocess ((void *) &do_test_call, NULL);
+
+  if (strcmp (result.err.buffer, expected) != 0)
+    {
+      support_record_failure ();
+      printf ("error:\n"
+	      "    expected: '%s'\n"
+	      "      actual: '%s'\n",
+	      expected, result.err.buffer);
+    }
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  const char *param_error = "--error";
+  const char *expected_error =
+    "test-argp: -1.000000-2.000000-3.000000-4.000000\n"
+    "Try `test-argp --help' or `test-argp --usage' for more information.\n";
+
+  const char *param_failure = "--failure";
+  const char *expected_failure =
+    "test-argp: -1.000000-2.000000-3.000000-4.000000\n";
+
+  argv[1] = (char *) param_error;
+  do_one_test (expected_error);
+
+  argv[1] = (char *) param_failure;
+  do_one_test (expected_failure);
+
+  return 0;
+}
+
+#include <support/test-driver.c>